Thesis (M.S.)--Joint Program in Oceanography/ Applied Ocean Science and Engineering, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 2005. / Bibliography: p.49-50.

Thesis (M.S.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1979. / Contract no.: N00014-77-C-096; NR 083-004. Includes bibliographical references (p. 132-133).

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). "June 2006." Includes bibliographical references (p. [169]-182) and index. Also available via the World Wide Web.

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Network coding is a promising technology that many researchers have advocated due to its potentially significant benefits to improve the efficiency of data transmission. In this thesis, we use simulations to evaluate the performance of different network topologies using network coding. By comparing the results with networks without network coding, we confirm that network coding can improve the network throughput. It also has a potential to decrease the end to end delay and improve the reliability. However, there are tradeoff (between delay and reliability) when network coding is used, and some limitations which we summarize. Finally, we have also implemented network coding to a three-dimensional underwater network by using parameters that truly reflect the underwater channel. Our performance evaluations show a better throughput and end-to-end delay but not the PDR (Packet Delivery Rate) in the underwater topology we used.

Separating oil/water emulsions is significant for the ecosystem and the petroleum and processing industry. To this end, we prepared an underwater superoleophobic membrane inspired by unique wettability of the fish scales. This membrane was fabricated by a facile vacuum filtration process of sepiolite nanofibers and chitosan, and after the cross-linking via glutaraldehyde, a self-standing membrane was obtained. The as-prepared membrane exhibited excellent capability of separating both the surfactant-free and surfactant-stabilized oil-in-water emulsions with high efficiency. This sepiolite fibrous membrane offers a convenient, reliable and efficient way for the large-scale de-emulsification process.

"This thesis discusses the archaeological literature concerning karst features: what information is available, the sites previously studied, the people who researched karst sites, and historic and prehistoric remains recovered from karst features. It describes specific sites, settlement studies related to karst features, and environmental reconstruction. As background, this thesis also describes geological and hydrological information concerning karst features, such as their sediment history, causes, and formation processes. It then presents geological information specific to one karst feature called Promise Sink. It also suggests a possible method to date sinkhole formation through pollen and floral analysis. Another facet of this thesis presents the results of a preliminary survey of a karst feature called Promise Sink. Through survey and excavation, the archaeological potential of Promis Sink is evaluated. A mapping gram provides documentation of Promise Sink on many levels: the surrounding area, surface features, physiology, and depth profile. An underwater survey of the sink also included subsurface testing which produced evidence of a prehistoric cultural component"--Introduction. / Typescript. / "Summer Semester, 1993." / "Submitted to the Department of Anthropology in Partial fulfillment of the requirements for the degree of Master of Arts." / Advisor: Rochelle Marrinan, Professor Directing Thesis. / Vita. / Includes bibliographical references (leaves 116-130).

In passive sonar systems, knowledge of low-frequency shipping noise is an important factor for target detection performance. However, an accurate model for the shipping noise structure is difficult to obtain, due to the varying distributions of ships and complicated underwater environment. This work characterizes low-frequency distant shipping noise observed in deep water environments as a function of receiver depth and vertical arrival structure for the case of a receiver below the conjugate depth. Surface shipping noise is examined using Monte Carlo simulations using a normal mode propagation model based on random distribution of ships and realistic parameters. The depth dependence of the simulated distant shipping noise is in agreement with published experimental measurements. A Vertical Line Array (VLA) is used to produce vertical beams that isolate the surface interference from nearby targets. Simulation results quantifying the beamformer output as a function of ocean environment, receiver aperture, and frequency are presented for both conventional and adaptive beamformers. The results suggest that conventional beamforming could detect the noisy target from both direct arrival and bottom bounce in the presence of distant shipping interferers and wind noise. However, the beamwidth of conventional beamforming is wider than that of adaptive beamforming. Once the motion effects of nearby ship interferences are considered, the adaptive beamforming using diagonal loading provides better detection performance. Preliminary adaptive beamforming results corresponding to different snapshot times show that motion effects can be minimized by using short observation times.

A design for a deep ocean hydrophone is proposed here. The hydrophone's sound sensing element is comprised of a capped end, piezoelectric cylinder. This sound sensing element is encased in an acoustic coupling fluid filled elastomeric boot. A small diameter tube communicates hydrostatic pressure from the coupling fluid to the interior of the sound sensing element for hydrostatic pressure compensation. The theoretical free field voltage sensitivity, the ratio of open circuit voltage to incident acoustic pressure, is predicted from mathematical model of the sound sensing element.